Planar stitched write head having write coil insulated with inorganic insulation

ABSTRACT

A write head has a second pole tip layer, a coil layer and a write coil insulation layer that are planarized at their top surfaces. A thin top insulation layer insulates the top of the coil layer from a yoke portion of the second pole piece which is connected to the second pole tip layer in the pole tip region and connected to a first pole piece layer in a back gap region. In a preferred embodiment the write gap layer extends throughout the yoke region and provides the only insulation between the first pole piece layer and the coil layer. Further, it is preferred that the write coil insulation layer be an inorganic material such as silicon dioxide (SiO 2 ). Several embodiments of the write head are provided along with novel methods of making.

REFERENCE TO RELATED APPLICATION

This is a divisional application of Ser. No., 09/212,119 filed Dec. 15,1998 U.S. Pat. No. 6,226,149.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a planar stitched write head having awrite coil that is insulated by inorganic insulation and, moreparticularly, to a write head having a second pole tip and coil layerthat are planarized with silicon dioxide located between the turns ofthe coil layer and between the coil layer and the second pole tip.

2. Description of the Related Art

The heart of a computer is an assembly that is referred to as a magneticdisk drive. The magnetic disk drive includes a rotating magnetic disk,write and read heads that are suspended by a suspension arm above therotating disk and an actuator that swings the suspension arm to placethe read and write heads over selected circular tracks on the rotatingdisk. The read and write heads are directly mounted on a slider that hasan air bearing surface (ABS). The suspension arm biases the slider intocontact with the surface of the disk when the disk is not rotating but,when the disk rotates, air is swirled by the rotating disk adjacent theABS to cause the slider to ride on an air bearing a slight distance fromthe surface of the rotating disk. When the slider rides on the airbearing the write and read heads are employed for writing magneticimpressions to and reading magnetic impressions from the rotating disk.The read and write heads are connected to processing circuitry thatoperates according to a computer program to implement the writing andreading functions.

The write head includes a coil layer embedded in first, second and thirdinsulation layers (insulation stack), the insulation stack beingsandwiched between first and second pole piece layers. A gap is formedbetween the first and second pole piece layers by a gap layer at an airbearing surface (ABS) of the write head and the pole piece layers areconnected at a back gap which is recessed from the ABS. Currentconducted to the coil layer induces a magnetic field across the gapbetween the pole pieces. This field fringes across the gap at the ABSfor the purpose of writing information in tracks on moving media, suchas a tape in a tape drive or in circular tracks on the aforementionedrotating disk.

Since the second pole tip is generally the last pole tip to passlocations on the circular track of a rotating disk, it is important thatthe width of the second pole tip be as narrow as possible for increasingthe track width density of the write head. The track width density isexpressed in the art as tracks per inch (TPI). Research efforts havenarrowed this track width thereby increasing magnetic disk drivecapabilities from kilobytes to megabytes to gigabytes. An ongoingproblem in the art, however, is producing a narrow second pole tip withgood side wall definition. The second pole tip is typically made bypatterning photoresist that has an opening where the second pole tip isto be plated. Unfortunately, the high topography behind the second poletip in typical write heads causes light to be reflected toward the ABSduring a light exposure step of the photoresist adjacent the desiredside walls of the second pole tip. This light exposes photoresistadjacent to the intended side walls which, upon developing, is removedand causes an irregularity when the second pole tip is plated. A maincontributor to this high topography is the insulation stack where thecoil layer is embedded and a seed layer covering the insulation stackthat is highly reflective. A reduction in this topography decreases whatis known in the art as “reflective notching” so as to produce a morehighly defined second pole tip.

The aforementioned high topography behind the second pole tip alsodegrades the performance of the yoke portion of the second pole piecewhich extends from the second pole tip to the back gap if the yoke isdeposited by sputtering techniques. When the yoke portion of the secondpole piece slopes down from the high topography to the second pole tip,it makes a curve which changes its magnetic properties. Some of theseproperties are uniaxial anisotropy field (H_(K)) and coercivity (H_(C)).Accordingly, it would be desirable to construct a planar second polepiece so that its magnetic properties would not be altered. Still afurther problem of the high topography is that after completion of thehead a thick overcoat layer is required in order to protect the yoke andpole tip portions of the head.

The aforementioned insulation stack is typically made from variouslayers of hard baked photoresist. In the construction sequence a layerof photoresist is spun on a wafer which is substantially planarizedthereacross. The photoresist layer is then photopatterned with lightexposing areas that are to be removed. The photoresist layer is thendeveloped with a developer which causes the exposed areas to dissolve sothey can be removed. The layer is then soft baked at a temperature of90°-120° C. which causes the layer to solidify with rounded edges. Afterconstructing a coil layer on a soft baked photoresist layer one or moreadditional photoresist layers may be constructed and soft baked in thesame manner. Thereafter, the photoresist layers are hard baked at atemperature of 230° C. which hardens the photoresist layers. Photoresistis an organic material that has a different coefficient of expansionthan other materials in the head, such as aluminum oxide (Al₂O₃)employed for the overcoat layer. When the magnetic head is operatingwithin a disk drive its operating temperature is at least above 100° C.This causes the hard baked photoresist insulation stack to expand morethan the overcoat layer which causes the overcoat layer to protrudebeyond the pole tips at the ABS. This protrusion can ruin the head orseverely degrade its performance. Further, the hard baking, of thephotoresist layers can result in loss of signal amplitude for some readsensors, such as spin valve sensors, in an adjoining read head. The hardbaked temperatures cause some intermixing of the materials of the layerswhich can significantly degrade their performance. Still further, thehard baked photoresist insulation stack has poor heat dissipation whichaggravates all of the aforementioned problems.

A recap of the aforementioned problems is as follows:

(1) Difficulty of second pole tip track width definition because ofsevere topography;

(2) Magnetic property change of a sputtered yoke portion of the secondpole piece as it curves over severe topography;

(3) Requirement for thick overcoat deposition;

(4) Protrusion of the overcoat layer at the ABS due to thermal expansionof a hard baked photoresist insulation stack;

(5) Signal amplitude loss of some spin valve sensors due to hard bakingof the photoresist layers; and

(6) Inadequate heat dissipation of the hard baked photoresist insulationstack.

SUMMARY OF THE INVENTION

The first three problems, mentioned hereinabove, are overcome in thepresent invention by providing a write head wherein the second pole tipand the write coil are planarized at their top surfaces. The write headincludes a first pole piece that is located in pole tip, yoke and backgap regions. The write gap layer is located on the first pole piece inthe pole tip region and a second pole tip layer is located on the writegap layer in the pole tip region. The coil layer, which has multiplespaced apart turns, is located on the first pole piece in the yokeregion and a write coil insulation layer is located between the turns ofthe coil and between the coil layer and the second pole tip layer. Thesecond pole tip layer, the coil layer and the insulation layer have topsurfaces which lie within a common flat surface. A thin top insulationlayer covers the top surface of the turns of the coil layer and a secondpole piece layer is on top of the top insulation layer, engages thesecond pole tip layer in the pole tip region and engages the first polepiece in the back gap region. The second pole tip can be constructedwith high track width definition because the patterned photoresist layeris on a flat surface instead of a sloping surface typically found in theprior art. The yoke of the second pole piece layer is nearly flat exceptfor the slight step of the top insulation layer which results insubstantially no change in magnetic properties of the yoke portion ofthe second pole piece. Further, because of the overall lack oftopography the overcoat deposition can be much thinner than thatemployed in the prior art.

The last three problems mentioned hereinabove are overcome in thepresent invention by employing an inorganic material for the write coilinsulation layer between the turns of the coil and between the coillayer and the second pole tip. This material is preferably silicondioxide (SiO₂). Silicon dioxide has a similar coefficient of expansionas aluminum oxide (Al₂O₃) thereby obviating the protrusion of thealuminum oxide overcoat layer at the ABS. Further, silicon dioxide doesnot require hard baking at a high temperature which can result indegrading some of the spin valve structures used in read heads. Stillfurther, the silicon dioxide is a better heat dissipator than hard bakedphotoresist.

After constructing the first pole piece, the write gap layer and thesecond pole tip layer a unique method is employed for forming the writecoil. First, a write coil mask is formed on the second pole tip layerand on the yoke and back gap regions of the first pole piece with awrite coil mask opening at a location where the write coil is to beformed. A write coil material layer is then formed on the write coilmask and in the write coil mask opening. The thicknesses of the writecoil mask and the write coil material layer are thicker than thethickness of the second pole tip layer. A grinding operation is thenemployed to grind away a portion of each of the write coil mask and thewrite coil material layer until the write coil is formed and the writecoil and the write coil mask have a common flat surface. The common flatsurface is instrumental in substantially planarizing the yoke portion ofthe second pole piece layer.

An object of the present invention is to provide a more highly definedsecond pole tip of a write head, planarize the yoke portion of thesecond pole piece layer and decrease the required thickness of anovercoat layer.

Another object is to provide a write head wherein the coefficient ofexpansions of the various layers of a write head are more similar so asto prevent protrusion of the overcoat layer at the ABS, eliminate hardbaking of photoresist insulation layers of the insulation stack so as toprevent degradation of a spin valve sensor in a read head and improveheat dissipation by providing an insulation stack with improved thermalconductivity.

A further object is to provide a write head which has a combination ofthe features set forth in the first and second objects hereinabove.

Still another object is to provide a unique method of making a writehead which has the features set forth hereinabove.

Other objects and attendant advantages of the invention will becomeapparent upon reading the specification taken together with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a planar view of an exemplary magnetic disk drive;

FIG. 2 is an end view of a slider with a magnetic head of the disk driveas seen in plane 2—2;

FIG. 3 is an elevation view of the magnetic disk drive wherein multipledisks and magnetic heads are employed;

FIG. 4 is an isometric illustration of an exemplary suspension systemfor supporting the slider and magnetic head;

FIG. 5 is an ABS view of the slider taken along in plane 5—5 of FIG. 2;

FIG. 6 is a partial view of the slider and magnetic head as seen inplane 6—6 of FIG. 2;

FIG. 7 is a partial ABS view of the slider taken along plane 7—7 of FIG.6 to show the read and write elements of the magnetic head;

FIG. 8 is a view taken along plane 8—8 of FIG. 6 with all material abovethe write coil removed;

FIG. 9 is a side elevation view of one embodiment of the presentinvention;

FIG. 10 is a view taken along plane 10—10 of FIG. 9;

FIG. 11 is a side elevation view of another embodiment of the presentinvention;

FIG. 12 is a view taken along plane 12—12 of FIG. 11;

FIG. 13 is a side elevation view of the construction of a first polepiece of the write head embodiment shown in FIGS. 9 and 10;

FIG. 14 is the same as FIG. 13 except the first pole piece has been ionmilled in order to provide a pedestal at the ABS and a recessed portiontherebehind;

FIG. 15 is the same as FIG. 14 except a layer of aluminum oxide (Al₂O₃)has been sputtered onto the first pole piece;

FIG. 16 is the same as FIG. 15 except the wafer has been chemicallymechanically polished (CMP) to provide a planar surface of the aluminumoxide (Al₂O₃) layer and the pedestal portion of the first pole piece;

FIG. 17 is the same as FIG. 16 except a write gap layer has been formed;

FIG. 18 is the same as FIG. 17 except a second pole tip has been formed;

FIG. 19 is the same as FIG. 18 except a write coil mask material layerof etchable material has been formed on the second pole tip layer in thepole tip region and on the first pole piece in the yoke region andtherebeyond;

FIG. 20 is the same as FIG. 19 except a photoresist layer has beenformed on the write coil mask material layer with photoresist layeropenings exposing portions of the write coil mask material layercorresponding to a location of the write coil;

FIG. 21 is the same as FIG. 20 except the write coil mask material layerhas been etched down to the write gap layer;

FIG. 22 is the same as FIG. 21 except the photoresist mask has beenremoved;

FIG. 23 is the same as FIG. 22 except a copper layer has been plated orsputter deposited on the wafer;

FIG. 24 is the same as FIG. 23 except the wafer has been chemicallymechanically polished (CMP) to provide a planar surface of the topsurfaces of the second pole tip, the write coil layer and the write coilinsulation material therebetween;

FIG. 25 is the same as FIG. 24 except a top insulation layer has beenformed on top of the write coil;

FIG. 26 is the same as FIG. 25 except a photoresist mask has been formedand the write coil insulation between the write coil and the write gaptherebelow have been etched away for a back gap connection;

FIG. 27 is the same as FIG. 26 except the yoke portion of the secondpole piece has been formed on top of the top insulation layer withconnections to the second pole tip in the pole tip region and to thefirst pole piece at the back gap;

FIG. 28 is a view taken along plane 28—28 of FIG. 27 with an overcoatlayer formed;

FIG. 29 illustrates in block form subsequent steps to complete themagnetic head and mount it in a disk drive;

FIG. 30 is a side elevation illustration of the first pole piece of theembodiment of the invention shown in FIGS. 11 and 12;

FIG. 31 is the same as FIG. 30 except a write gap layer has been formedthereon;

FIG. 32 is the same as FIG. 31 except the second pole tip has beenformed in the pole tip region;

FIG. 33 is the same as FIG. 32 except a write coil mask material layerof etchable material has been formed on the second pole tip in the poletip region and on the first pole piece in the yoke region andtherebeyond;

FIG. 34 is the same as FIG. 33 except a photoresist layer has beenphotopatterned on the write coil mask material layer with openingsexposing a portion of the write coil mask material layer at a locationwhere the write coil is to be formed;

FIG. 35 is the same as FIG. 34 except reactive ion etching (RIE) hasbeen implemented to etch the write coil mask material layer withopenings down to the gap layer;

FIG. 36 is the same as FIG. 35 except the photoresist layer has beenremoved;

FIG. 37 is the same as FIG. 36 except a write coil material layer hasbeen plated or sputter deposited;

FIG. 38 is the same as FIG. 37 except the wafer has been chemicallymechanically polished (CMP) to provide a planar surface of the topsurface of the second pole tip, the coil layer and the write coilinsulation material therebetween;

FIG. 39 is the same as FIG. 38 except a top insulation layer has beenformed on top of the write coil layer;

FIG. 40 is the same as FIG. 39 except a photoresist layer has beenphotopatterned and the wafer has been etched to provide an opening atthe back gap;

FIG. 41 is the same as FIG. 40 except the photoresist layer has beenremoved and the yoke portion of the second pole piece has been formed ontop of the write coil insulation layer and connected to the second poletip in the pole tip region and connected to the first pole piece in theback gap region; and

FIG. 42 is a view taken along plane 42—42 of FIG. 41 with an overcoatlayer formed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Magnetic Disk Drive

Referring now to the drawings wherein like reference numerals designatelike or similar parts throughout the several views, FIGS. 1-3 illustratea magnetic disk drive 30. The drive 30 includes a spindle 32 thatsupports and rotates a magnetic disk 34. The spindle 32 is rotated by amotor 36 that is controlled by a motor controller 38. A combined readand write magnetic head 40 is mounted on a slider 42 that is supportedby a suspension 44 and actuator arm 46. A plurality of disks, slidersand suspensions may be employed in a large capacity direct accessstorage device (DASD) as shown in FIG. 3. The suspension 44 and actuatorarm 46 position the slider 42 so that the magnetic head 40 is in atransducing relationship with a surface of the magnetic disk 34. Whenthe disk 34 is rotated by the motor 36 the slider is supported on a thin(typically, 0.05 μm) cushion of air (air bearing) between the surface ofthe disk 34 and the air bearing surface (ABS) 48. The magnetic head 40may then be employed for writing information to multiple circular trackson the surface of the disk 34, as well as for reading informationtherefrom. Processing circuitry 50 exchanges signals, representing suchinformation, with the head 40, provides motor drive signals for rotatingthe magnetic disk 34, and provides control signals for moving the sliderto various tracks. In FIG. 4 the slider 42 is shown mounted to asuspension 44. The components described hereinabove may be mounted on aframe 54 of a housing 55, as shown in FIG. 3.

FIG. 5 is an ABS view of the slider 42 and the magnetic head 40. Theslider has a center rail 56 that supports the magnetic head 40, and siderails 58 and 60. The rails 56, 58 and 60 extend from a cross rail 62.With respect to rotation of the magnetic disk 34, the cross rail 62 isat a leading edge 64 of the slider and the magnetic head 40 is at atrailing edge 66 of the slider.

FIG. 6 is a side cross-sectional elevation view of the merged MR head40, which includes a write head portion 70 and a read head portion 72,the read head portion employing a sensor 74. FIG. 7 is an ABS view ofFIG. 6. The sensor 74 is sandwiched between first and second gap layers76 and 78, and the gap layers are sandwiched between first and secondshield layers 80 and 82. In response to external magnetic fields, theresistance of the sensor 74 changes. A sense current I_(S) conductedthrough the sensor causes these resistance changes to be manifested aspotential changes. These potential changes are then processed asreadback signals by the processing circuitry 50 shown in FIG. 3.

The write head portion of the merged MR head includes a coil layer 84sandwiched between first and second insulation layers 86 and 88. A thirdinsulation layer 90 may be employed for planarizing the head toeliminate ripples in the second insulation layer caused by the coillayer 84. The first, second and third insulation layers are referred toin the art as an “insulation stack”. The coil layer 84 and the first,second and third insulation layers 86, 88 and 90 are sandwiched betweenfirst and second pole piece layers 92 and 94. The first and second polepiece layers 92 and 94 are magnetically coupled at a back gap 96 andhave first and second pole tips 98 and 100 which are separated by awrite gap layer 102 at the ABS. As shown in FIGS. 2 and 4, first andsecond solder connections 104 and 106 connect leads from the spin valvesensor 74 to leads 112 and 114 on the suspension 44, and third andfourth solder connections 116 and 118 connect leads 120 and 122 from thecoil 84 (see FIG. 8) to leads 124 and 126 on the suspension.

First Embodiment of the Invention

The first embodiment 200 of the present invention is shown in FIGS. 9and 10. The first embodiment of the write head includes a first polepiece (P1) 202 which has a pedestal portion 204 at the ABS and arecessed portion 206 which may extend from the pedestal portion to andbeyond the back gap (BG). The pedestal portion 204 and the recessedportion 206 provide a recess wherein recessed insulation material 208 islocated and is planar with a top surface of the pedestal portion 204. Apreferred material for the recessed insulation material is aluminumoxide (Al₂O₃). A write gap layer 210 is located on the pedestal portion204 in the pole tip region and may extend from the pole tip region toand past the back gap (BG) if desired. A second pole tip (P2) 212 islocated on the write gap layer 210 and forms a portion of the ABS. Awrite coil layer 214 is located on the write gap layer 210 in the yokeregion of the head and winds around the back gap (BG). A write coilinsulation layer 216 is located between turns of the coil layer 214 andbetween the coil layer and the second pole tip 212. The top surfaces ofthe second pole tip layer 212, the coil layer 214 and the write coilinsulation layer 216 form a common flat surface. A top insulation layer220 insulates the top surface of the coil layer 214.

A yoke portion of the second pole piece (P2 yoke) 222 is on the topinsulation layer 220 and is magnetically connected to the second poletip 212 in the pole tip region and is magnetically connected to thefirst pole piece 206 at the back gap (BG). The recessed insulation layer208, the write gap layer 210 and the top insulation layer 220 arepreferably aluminum oxide (Al₂O₃) and the write coil insulation layer216 is preferably silicon dioxide (SiO₂). It can be seen from thisconstruction that the yoke portion 222 of the second pole piece issubstantially planar except for the minor step of the top insulationlayer 220. The top insulation layer 220, however, can be very thin, inthe order of 1,000 Å to 2,000 Å. Essentially, the yoke portion 222 ofthe second pole piece is substantially flat so as to prevent a curveover an insulation stack which is shown by the second pole piece layer94 in FIG. 6.

The silicon dioxide (SiO₂) material of the write coil insulation layer216 has a coefficient of expansion close to the coefficient of expansionof the overcoat layer 224 which covers the write head. Accordingly, uponexpansion due to heat the write coil insulation layer 216 will not forcethe overcoat layer 224 beyond the ABS which is a potential problemcaused by the insulation stack comprising layers 86, 88 and 90 in FIG.6.

Below the write head is a read head which includes a first shield layer230 and a second shield layer. In a merged head the second shield layermay comprise the first pole piece 202 of the write head. First andsecond read gap layers 232 and 234 are located between the first andsecond shield layers 230 and 202 and a read sensor 236 is locatedbetween the first and second read gap layers 232 and 234. When the layer202 is employed as the first pole piece for the write head and a secondshield layer for the read head, the combined head structure is referredto as a merged head. When these layers are separate the combined head isreferred to as a piggyback head.

It should be noted that the write coil insulation layer 216 may also belocated between turns of the coil layer behind the back gap (BG). FIG.10 shows an ABS illustration of FIG. 9 where the side walls 240 and 242of the second pole tip 212 are highly defined because the write head isplanar behind the second pole tip 212. Accordingly, patternedphotoresist employed for constructing the second pole tip 212 will notreceive reflective light from the high topography of an insulationstack, as shown in FIG. 6, during the light exposure step of thephotoresist. Further, the overcoat layer 224 can be made thin because itdoes not have to account for the high topography caused by theinsulation stack in FIG. 6.

Second Embodiment of the Present Invention

FIGS. 11 and 12 show a second embodiment 250 of the present write head.The write head 250 includes a first pole piece 252 which is planar fromthe ABS to and past the back gap (BG). The write gap layer 254 islocated on the first pole piece 252 from the ABS to at least the backgap (BG). The write gap layer 254 serves as an etch step in thisembodiment, which will be described in detail under the method ofconstruction of the second embodiment. A second pole tip layer 256 islocated on the write gap layer 254 in the pole tip region and a writecoil layer 258 is located on the write gap layer 254 in the yoke region.A write coil insulation layer 260 is located between the turns of thewrite coil 258 and between the write coil and the second pole tip layer256. Top surfaces of the second pole tip 256, the write coil layer 258,and the write coil insulation layer 260 form a common flat surface. Thetop insulation layer 262 is located on the top flat surface andinsulates the top surface of the coil layer 258.

A yoke portion 264 of a second pole piece is located on the topinsulation layer 262 and is magnetically connected to the second poletip layer at 264 and is magnetically connected to the first pole piece252 at the back gap (BG). It should be noted in this embodiment that thewrite coil layer 254 is the only layer insulating the coil layer 258from the first pole piece 252. Accordingly, the first pole piece 252 ofthe embodiment in FIG. 11 will have greater flux carrying capabilitythan the first pole piece of the embodiment shown in FIG. 9.

The definition of the side walls 270 and 272 of the second pole tiplayer 256, shown in FIG. 12, are well-defined in the same manner as theside walls 240 and 242, shown in FIG. 10. Further, the yoke portion 264of the second pole piece is substantially flat in the same manner as theyoke portion 222 of the second pole piece in FIG. 9. Again, the writegap layer 254 and the top insulation layer 262 are preferably aluminumoxide (Al₂O₃) and the write coil insulation layer is preferably silicondioxide (SiO₂). The read head below this write head is the same as theread head shown in FIG. 9.

Method of Making First Embodiment

A method of making the first write head embodiment shown in FIGS. 9 and10 is shown in FIGS. 13-28. In FIG. 13 a first pole piece material layer300 is formed by any suitable means such as photopatterning withphotoresist and plating. The first pole piece material layer 300 may beformed on the second read gap layer 234 shown in FIG. 9. The left sideof the first pole piece material layer 300 is an air bearing surface(ABS) site which is formed after all of the heads are completed on awafer and diced into rows of heads. Accordingly, the first pole piecematerial layer 300 actually covers an entire wafer and then issubsequently processed, which will be described next.

In FIG. 14 the first pole piece layer 300 in FIG. 13 has beenphotopatterned and plated to provide a first pole piece 302 that has apedestal portion 304 in a pole tip region and a recessed portion 306which extends through the yoke region to at least the back gap (BG).

In FIG. 15 a recessed insulation material layer 308 is deposited by anysuitable means such as sputtering, which covers the pedestal 304 and therecessed portion 306 of the first pole piece. It is important that thethickness of the recessed insulation layer 308 be thicker and the heightof the pedestal 304 above the recessed portion 306. In FIG. 16 the waferis chemically mechanically polished (CMP) which forms the recessedinsulation layer 310 with a top surface 312 that is planar with a topsurface 314 of the pedestal portion 304 of the first pole piece. In FIG.17 a write gap layer 316 is formed on the top surface of the pedestalportion 304 of the first pole piece layer. It is preferred that thewrite gap layer 316 also cover the recessed insulation layer 310 so asto eliminate a masking step. In FIG. 18 a second pole tip layer 318 isformed on the write gap layer 316 in the pole tip region.

In FIG. 19 a write coil insulation material layer 320 is formed on thesecond pole tip layer 318 and on the write gap layer 316. It isimportant that the thickness of the layer 320 be thicker than thethickness of the second pole tip layer 318, which will be explained inmore detail hereinafter. In FIG. 20 a photoresist material layer hasbeen spun on the head and patterned to provide a patterned photoresistlayer 322 on the write coil insulation material layer 320 with aspiral-shaped opening 324 which exposes a portion of the top surface ofthe write coil insulation material layer 320 where a write coil is to beformed. Alternatively, an inorganic insulation material layer, such asAl₂O₃ or NiFe can be prepared for reactive ion etching (RIE) imagetransfer and then subsequently removed by chemical mechanical polishing(CMP). A preferable material for the write coil insulation materiallayer 320 is silicon dioxide (SiO₂), which is a material which can beetched by reactive ion etching (RIE) with a fluorine base such as CF₄,CHF₃, C₂F₆ or SF₆. In FIG. 21 the reactive ion etch (RIE) etchesopenings 326 in the write coil insulation material layer 320 where awrite coil is to be formed. It should be noted that the reactive ionetching (RIE) is stopped at the gap layer 316 or at the recessedinsulation layer 308 if the write gap layer is omitted from the yokeregion. The gap layer 316 and the recessed insulation layer 308 arepreferably aluminum oxide (Al₂O₃) which is not etched significantly bythe fluorine-based RIE. Accordingly, when silicon dioxide (SiO₂) isemployed for the write coil insulation material layer 320 and aluminumoxide (Al₂O₃) is employed for the write gap layer 316 or the insulationlayer 308 the fluorine-based reactive ion etch is selective to the writecoil insulation material layer 320.

In FIG. 23 a seed layer has been sputter deposited followed by formationof a write coil material layer 328 by any suitable means such as platingor sputter deposition. It is important that the thickness of this layerbe thicker than the height of the second pole tip 318. In FIG. 24 thewafer is chemically mechanically polished (CMP) which forms a write coillayer 330 and the previously mentioned write coil insulation materiallayer 320 into a write coil insulation layer 332 which is locatedbetween the turns of the coil and between the coil layer 330 and thesecond pole tip 318. Top surfaces of the second pole tip 318, the coillayer 330 and the write coil insulation layer 332 form a common flatsurface. This is important for subsequent construction of the secondpole piece.

In FIG. 25 a top insulation layer 334 is formed on top of the topsurface of the coil layer 330 by any suitable means such asphotopatterning with photoresist and sputter deposition of aluminumoxide (Al₂O₃) followed by a lift off process. In FIG. 26 the wafer isphotopatterned with patterned photoresist 336 that has an opening 338where a back gap (BG) is to be formed. The wafer is then etched to etchthrough the write coil insulation layer 332, the write gap layer 316 andthe recessed insulation layer 310 to expose the first pole piece in theback gap region. In FIG. 27 the yoke portion 340 of the second polepiece is formed on top of the top insulation layer 334 with a magneticconnection with the second pole tip 318 at 342 and a connection with thefirst pole piece at 344 in the back gap region.

FIG. 28 is an ABS illustration of FIG. 27 after formation of an overcoatlayer 346. The material of the overcoat layer is preferably aluminumoxide (Al₂O₃). After construction of rows and columns of heads on awafer, the wafer is diced into rows of heads and lapped to form the airbearing surface (ABS) as shown in FIG. 29. The rows and heads are thendiced into separate heads and mounted on a disk drive for operation.

Method of Construction of the Second Embodiment of the Write Head

FIGS. 30-42 illustrate the method of constructing the second embodimentof the write head shown in FIGS. 11 and 12. In FIG. 30 a first polepiece layer 400 is constructed on the second read gap layer 234 shown inFIG. 11. The first pole piece layer 400 extends from an ABS site to atleast the back gap region. In FIG. 31 a write gap layer 416 is formed onthe first pole piece layer 400 from the ABS site to at least to the backgap region. The write gap layer may be formed by any suitable means suchas sputter deposition and is preferably aluminum oxide (Al₂O₃). In FIG.32 a second pole tip layer 418 is formed on the write gap layer 416 inthe pole tip region.

In FIG. 33 a write coil insulation material layer 420 is formed on thesecond pole tip layer 418 and on the write gap layer 416. It isimportant that the thickness of the layer 420 be thicker than thethickness of the second pole tip layer 418, which will be explained inmore detail hereinafter. In FIG. 34 a photoresist material layer hasbeen spun on the head and patterned to provide a patterned photoresistlayer 422 on the write coil insulation material layer 420 with aspiral-shaped opening 424 which exposes a portion of the top surface ofthe write coil insulation material layer 420 where a write coil is to beformed. A preferred material for the write coil insulation materiallayer 420 is silicon dioxide (SiO₂) which is a material which can beetched by reactive ion etching (RIE) with a fluorine base such as CF₄,CHF₃, C₂F₆ or SF₆. In FIG. 35 the reactive ion etch (RIE) etchesopenings 426 in the write coil insulation material layer 420 where awrite coil is to be formed. It should be noted that the reactive ionetching (RIE) is stopped at the gap layer 416. The gap layer 416 ispreferably aluminum oxide (Al₂O₃) which is not etched by thefluorine-based RIE. Accordingly, when silicon dioxide (SiO₂) is employedfor the write coil insulation material layer 420 and aluminum oxide(Al₂O₃) is employed for the write gap layer 416 the fluorine-basedreactive ion etch is selective to the write coil insulation materiallayer 420 with respect to the write gap layer 416. Accordingly, thewrite gap layer 416 provides an etch stop so that the reactive ion etch(RIE) sell not etch into the first pole piece layer 400. Further, thewrite gap layer 416 will serve as the only insulation layer between thefirst pole piece 400 and a write head to be subsequently constructed.

In FIG. 37 a seed layer has been sputter deposited followed by formationof a write coil material layer 428 by any suitable means such as platingor sputter deposition. It is important that the thickness of this layerbe thicker than the height of the second pole tip 418. In FIG. 38 thewafer is chemically mechanically polished (CMP) which forms a write coillayer 430 and the previously mentioned write coil insulation materiallayer 420 into a write coil insulation layer 432 which is locatedbetween the turns of the coil and between the coil layer 430 and thesecond pole tip 418. Top surfaces of the second pole tip 418, the coillayer 430 and the write coil insulation layer 432 form a common flatsurface. This is important for subsequent construction of the secondpole piece.

In FIG. 39 a top insulation layer 434 is formed on top of the topsurface of the coil layer 430 by any suitable means such asphotopatterning with photoresist and sputter deposition of aluminumoxide (Al₂O₃). In FIG. 40 the wafer is photopatterned with patternedphotoresist 436 that has an opening 438 where a back gap (BG) is to beformed. The wafer is then etched to etch through the write coilinsulation layer 432 and the write gap layer 416 to expose the firstpole piece in the back gap region. In FIG. 41 the yoke portion 440 ofthe second pole piece is formed on top of the top insulation layer 434making a magnetic connection with the second pole tip 418 at 442 andmaking a magnetic connection with the first pole piece at 444 in theback gap region.

FIG. 42 is an ABS illustration of FIG. 41 after formation of an overcoatlayer 446. The material of the overcoat layer is preferably aluminumoxide (Al₂O₃). After construction of rows and columns of heads on awafer, the wafer is diced into rows of heads and lapped to form the airbearing surface (ABS) as shown in FIG. 29. The rows and heads are thendiced into separate heads and mounted on a disk drive for operation.

Clearly, other embodiments and modifications of this invention willoccur readily to those of ordinary skill in the art in view of theseteachings. For instance, in a broad aspect of the invention the secondpole piece in FIG. 11 may be stitched, as shown, or non-stitched whereinthe top surfaces of the coil layer and the non-organic intercoil layer260 are coplanar. Therefore, this invention is to be limited only byfollowing claims, which include all such embodiments and modificationswhen viewed in conjunction with the above specification and accompanyingdrawings.

We claim:
 1. A magnetic head that has an air bearing surface (ABS) and ayoke region between a pole tip region and a back gap region wherein thepole tip region is partially bounded by said ABS, comprising: a firstpole piece that is located in said pole tip, yoke and back gap regions;a write gap layer on the first pole piece in said pole tip region; asecond pole tip layer with a first surface on the write gap layer in thepole tip region; a coil layer having multiple spaced apart turns with asecond surface on the first pole piece in the yoke region; a write coilinsulation layer with a third surface located between the turns of thecoil layer and between the coil layer and the second pole tip layer; thefirst, second and third surfaces forming a first common flat surface; atop insulation layer on the common flat surface covering the secondsurface of the turns of the coil layer; and a second pole piece layer onthe top insulation layer and engaging the second pole tip layer in thepole tip region and engaging the first pole piece in the back gapregion.
 2. A magnetic head as claimed in claim 1 wherein the write gaplayer extends through the yoke region.
 3. A magnetic head as claimed inclaim 1 wherein the write gap layer is the only layer insulating thecoil layer from the first pole piece.
 4. A magnetic head as claimed inclaim 3 wherein the recessed insulation layer, the write gap layer andthe top insulation layer are aluminum oxide (Al₂O₃) and the write coilinsulation layer is silicon dioxide (SiO₂).
 5. A magnetic head asclaimed in claim 1 including: the first pole piece having a pedestal inthe pole tip region and a recessed portion in the yoke region; and anonconductive electrically insulative recessed insulation layer locatedin said recessed portion of the first pole piece.
 6. A magnetic head asclaimed in claim 5 wherein the recessed insulation layer, the write gaplayer and the top insulation layer are aluminum oxide (Al₂O₃) and thewrite coil insulation layer is silicon dioxide (SiO₂).
 7. A magnetichead as claimed in claim 1 including a read that comprises: first andsecond nonmagnetic electrically insulative first and second gap layers;a read sensor and first and second lead layers located between the firstand second gap layers; a ferromagnetic first shield layer; the first andsecond gap layers being located between the first shield layer and thefirst pole piece.
 8. A magnetic head as claimed in claim 7 wherein thewrite gap layer is the only layer insulating the coil layer from thefirst pole piece.
 9. A magnetic head as claimed in claim 7 including:the first pole piece having a pedestal in the pole tip region and arecessed portion in the yoke region; and a nonconductive electricallyinsulative recessed insulation layer located in said recessed portion ofthe first pole piece.
 10. A magnetic disk drive that includes a magnetichead that has an air bearing surface (ABS) and a yoke region between apole tip region and a back gap region wherein the pole tip region ispartially bounded by said ABS, the disk drive comprising: the magnetichead including a combined read head and write head; the read headincluding: first and second ferromagnetic shield layers: first andsecond nonmagnetic electrically insulative gap layers located betweenthe first and second ferromagnetic shield layers; a read sensorresponsive to applied magnetic fields and first and second lead layersconnected to the read sensor; the read sensor and the first and secondlead layers being located between the first and second gap layers; thewrite head including: a first pole piece that is located in said poletip, yoke and back gap regions, the first pole piece being a commonlayer with said second shield layer; a write gap layer on the first polepiece in said pole tip region; a second pole tip layer with a firstsurface on the write gap layer in the pole tip region; a coil layerhaving multiple spaced apart turns with a second surface on the firstpole piece in the yoke region; a write coil insulation layer with athird surface located between the turns of the coil layer and betweenthe coil layer and the second pole tip layer; the first, second andthird surfaces forming a first common flat surface; a top insulationlayer on the common flat surface covering the second surface of theturns of the coil layer; and a second pole piece layer on the topinsulation layer and engaging the second pole tip layer in the pole tipregion and engaging the first pole piece in the back gap region; ahousing; a magnetic disk rotatably supported in the housing; a supportmounted in the housing for supporting the magnetic head with its ABSfacing the magnetic disk so that the magnetic head is in a transducingrelationship with the magnetic disk; means for rotating the magneticdisk; positioning means connected to the support for moving the magnetichead to multiple positions with respect to said magnetic disk; andprocessing means connected to the magnetic head, to the means forrotating the magnetic disk and to the positioning means for exchangingsignals with the merged magnetic head, for controlling movement of themagnetic disk and for controlling the position of the magnetic head. 11.A magnetic disk drive as claimed in claim 10 wherein the write gap layeris the only layer insulating the coil layer from the first pole piece.12. A magnetic disk drive as claimed in claim 11 wherein the recessedinsulation layer, the write gap layer and the top insulation layer arealuminum oxide (Al₂O₃) and the write coil insulation, layer is silicondioxide (SiO₂).
 13. A magnetic disk drive as claimed in claim 10including: the first pole piece having a pedestal in the pole tip regionand a recessed portion in the yoke region; and a nonconductiveelectrically insulative recessed insulation layer located in saidrecessed portion of the first pole piece.
 14. A magnetic disk drive asclaimed in claim 13 wherein the recessed insulation layer, the write gaplayer and the top insulation layer are aluminum oxide (Al₂O₃) and thewrite coil insulation layer is silicon dioxide (SiO₂).
 15. A magnetichead that has an air bearing surface (ABS) and a yoke region between apole tip region and a back gap region wherein the pole tip region ispartially bounded by said ABS, comprising: a first pole piece that islocated in said pole tip, yoke and back gap regions; a write gap layeron the first pole piece in said pole tip region; a second pole piecelayer with a first surface on the write gap layer in the pole tipregion; a coil layer having multiple spaced apart turns with a secondsurface on the first pole piece in the yoke region; a write coilnon-organic insulation layer with a third surface located between theturns of the coil layer and between the coil layer and the second poletip layer; and the second and third surfaces forming a first common flatsurface; a top insulation layer on the common flat surface covering thesecond surface of the turns of the coil layer; and said second polepiece layer being on the top insulation layer and engaging the firstpole piece in the back gap region.
 16. A magnetic head as claimed inclaim 15 including: the second pole piece layer having a second pole tipportion and a second yoke portion; the second pole tip portion havingsaid first surface and the yoke portion being on the top insulationlayer and being connected to the first pole piece in the back gapregion; and the first, second and third surfaces being coplanar.
 17. Amagnetic head as claimed in claim 16 including: the write gap layerextending through the yoke region; the second pole tip portion having afourth surface, the coil layer having a fifth surface and thenon-organic insulation layer having a sixth surface; and the fourth,fifth and sixth surfaces being located on the write gap layer and beingcoplanar.